@remarks The first pair of parameters give the number of pixels per
'scroll step', i.e. amount moved when the up or down
scroll arrows are pressed. The second pair gives the
length of scrollbar in scroll steps, which sets the
size of the virtual window.
@remarks The first pair of parameters give the number of pixels per
'scroll step', i.e. amount moved when the up or down
scroll arrows are pressed. The second pair gives the
length of scrollbar in scroll steps, which sets the
size of the virtual window.